refs #8912. Start work looking at pyplot.plot.

Code/Mantid/MantidPlot/mantidplotpy/matplotlib/pyplot.py

+import numpy as np
+from mantid.api import MatrixWorkspace as MatrixWorkspace
+
+def __is_array(arg):
+    return isinstance(arg, list) or isinstance(arg, np.ndarray) 
+
+def __is_workspace(arg):
+    return isinstance(arg, MatrixWorkspace)
+
+def __is_array_of_workspaces(arg):
+    return __is_array(arg) and len(arg) > 0 and __is_workspace(arg[0])
+
+
+def __plot_as_workspace(arg):
+    print "TODO plot_as_workspace"
+    pass
+
+def __plot_as_workspaces(arg):
+    print "TODO plot as workspaces"
+    pass
+
+def __plot_as_array(arg):
+    print "TODO plot as array"
+    pass
+
+
+
+def plot (y, x=None, marker=None):
+    print type(y)
+    if __is_array(y):
+        if __is_array_of_workspaces(y):
+            __plot_as_workspaces(y)
+        elif __is_workspace(y):
+            __plot_as_workspace(y)
+        else:
+            __plot_as_array(y)
+    else:
+        raise ValueError("Cannot plot argument of type " + str(type(y)) )
+         
+